User Manual

Filter
This control selects the filtering algorithm used when applying a blur to the matte.
 Box: This is the fastest method but at reduced quality. Box is best suited for minimal
amounts of blur.
 Bartlett: Otherwise known as a Pyramid filter, Bartlett makes a good compromise
between speed and quality.
 Multi-box: When selecting this filter, the Num Passes slider appears and lets you
control the quality. At 1 and 2 passes, results are identical to Box and Bartlett,
respectively. At 4 passes and above, results are usually as good as Gaussian, in less
time and with no edge “ringing.”
 Gaussian: The Gaussian filter uses a true Gaussian approximation and gives excellent
results, but it is a little slower than the other filters. In some cases, it can produce an
extremely slight edge “ringing” on floating-point pixels.
Blur
This blurs the edge of the matte using the method selected in the Filter menu. A value of zero
results in a sharp, cutout-like hard edge. The higher the value, the more blur.
Clipping Mode
This option determines how edges are handled when performing domain of definition
rendering. This is profoundly important when blurring the matte, which may require samples
from portions of the image outside the current domain.
 Frame: The default option is Frame, which automatically sets the node’s domain of
definition to use the full frame of the image, effectively ignoring the current domain
of definition. If the upstream DoD is smaller than the frame, the remaining area in the
frame is treated as black/transparent.
 Domain: Setting this option to Domain respects the upstream domain of definition
when applying the node’s effect. This can have adverse clipping effects in situations
where the node employs a large filter.
 None: Setting this option to None does not perform any source image clipping at all.
This means that any data required to process the node’s effect that is usually outside
the upstream DoD is treated as black/transparent.
Contract/Expand
This slider shrinks or grows the semitransparent areas of the matte. Values above 0.0 expand
the matte, while values below 0.0 contract it.
This control is usually used in conjunction with the blur to take the hard edge of a matte and
reduce fringing. Since this control affects only semitransparent areas, it has no effect on a
matte’s hard edge.
Gamma
Matte Gamma raises or lowers the values of the matte in the semitransparent areas. Higher
values cause the gray areas to be more opaque, and lower values cause the gray areas to be
more transparent. Wholly black or white regions of the matte remain unaffected.
Invert
Selecting this checkbox inverts the matte, causing all transparent areas to be opaque and all
opaque areas to be transparent.
Chapter – 98 Matte Nodes 2164